Using RE24 To Account For Situational Hitting

Tigers designated hitter Victor Martinez is adding runs with situational hitting
(Photo Credit: Bruce Hemmelgarn, USA Today Sports)

Many fans grumble that statistics such as OPS and Batting Runs do not account for situational hitting.  For example, if Tigers slugger Miguel Cabrera singles with a runners on second and third to drive home two runs, he gets the same credit as he would for a single with the bases empty.  Some will argue that this is not fair because he contributes more to his team in the former scenario than the latter.  In this post, I will re-introduce an under-utilized statistic which accounts for a hitter's performance in different circumstances. 

Traditional fans like to address situational hitting with the familiar Runs Batted In statistic, but that is a team dependent measure.  A player has more or less opportunity to drive in runs depending on who is batting in front of him.  Thus, a player gets acknowledged for driving home runs, but does not get penalized for failing to drive home runs.  So, the RBI count is not an adequate measure of situational hitting.

Other fans point to batting average with runners in scoring position, but that is based on a limited number of plate appearances.  It also doesn't consider the number of outs, the specific base runners (e.g. bases loaded versus second base only) or the type of hit (single, double, triple or home run).  Moreover, it ignores a player's performance when no runners are in scoring position.  

What we want is a statistic which gives a player credit for everything he does including situational hitting.  Batting Runs Above Average by the 24 Base/Out States (RE24) - found at FanGraphs - does just that.  The RE24 statistic is also sometimes referred to as "Value Added".  This metric will give a player credit for his singles, doubles, and all other events, and gives him extra credit for hits occurring with runners on base.  It even gives him points for a scenario which most other metrics ignore - moving a runner over with a ground out.  On the other hand, it subtracts extra points for hitting into double plays.

In past posts, I discussed just plain Batting Runs or Weighted Runs Above Average (wRAA or RAA) which is an estimate of how many runs a player contributed to his team beyond what an average hitter would have contributed in his place.  The RE24 metric is similar to RAA except that it uses base/out states in the calculation.  An example of a base/out state is "runners at first and third and one out".  There are 24 possible base/out states and RE24 takes all of them into consideration. 

In the calculation of RAA, a double with the bases loaded and two outs counts the same (0.770 runs) as a double with the bases empty and no outs.  Conversely, RE24 counts the bases loaded double more than the bases empty double (2.544 versus 0.632) because it does more to increase the expected runs scored in the inning.

The RE24 metric for one at bat gives us the difference between run expectancy at the beginning and end of a play.  For example, suppose Cabrera bats with a runner on first and one out. In that situation, we would expect 0.556 runs to score by the end of the inning.  Assume that Cabrera then doubles, putting runners on second and third with one out. In that situation, we would expect 1.447 runs to score by the end of the inning. Therefore, Cabrera's double is worth 0.891 runs.

Summing RE24 over all of a batter’s plate appearances yields his season total RE24. For
example, Cabrera has a RE24 of 30.7 this year.  So, by that measure, he contributed about 31 runs above what an average batter would have been expected to contribute given the same opportunities. This is higher than his 27.7 RAA, which means that Cabrera has been especially good in situations with high run expectancy and has added more to his team’s runs total than RAA indicates.  We can estimate that he has contributed an extra 3 runs with his situational hitting.

Since situational hitting is largely (although not completely) random, RE24 is less predictive than RAA and should not generally be used as a measure of ability based on one year of data.  It does become more predictive over multiple years and may be a more representative measure of ability over a career than RAA. Regardless of what it says about talent though, it is a good alternative to RAA for looking at past performance. 

Table 1 below shows that Angels center fielder Mike Trout (46.7) and Blue Jays left fielder Melky Cabrera (37.5) rank first and second in RFE24.  Cabrera's RE24 is 12 runs higher than his RAA which tells us that he has been very good in situations with high run expectancy.  On the flip side, Blue Jays slugger Jose Bautista has a differential of -10.8 (24.2 on RE24 versus 35.0 on RAA) suggesting that he does not do as well in spots where he has a greater chance to contribute runs.  

Table 1: AL RE24 Leaders as of August 21, 2014

Name	Team	RE24	RAA	RE24-RAA
Mike Trout	Angels	46.7	37.8	8.9
Melky Cabrera	Blue Jays	37.5	25.5	12.0
Victor Martinez	Tigers	34.5	31.4	3.1
Michael Brantley	Indians	33.6	29.2	4.4
Jose Abreu	White Sox	33.2	34.9	-1.7
Robinson Cano	Mariners	31.7	25.0	6.7
David Ortiz	Red Sox	31.4	22.9	8.5
Miguel Cabrera	Tigers	30.7	27.7	3.0
Adrian Beltre	Rangers	26.8	24.8	2.0
Jose Bautista	Blue Jays	24.2	35.0	-10.8
Josh Donaldson	Athletics	23.1	16.9	6.2
Edwin Encarnacion	Blue Jays	21.6	28.6	-7.0
Kyle Seager	Mariners	21.0	18.4	2.6
Alex Gordon	Royals	20.6	17.6	3.0
Brandon Moss	Athletics	19.5	15.5	4.0
Conor Gillaspie	White Sox	17.9	12.9	5.0
Adam Eaton	White Sox	17.3	10.7	6.6
Lonnie Chisenhall	Indians	16.7	12.9	3.8
David Murphy	Indians	16.2	1.0	15.2
Jacoby Ellsbury	Yankees	14.7	6.2	8.5

Data source: FanGraphs.com

Table 2 shows that designated hitter Victor Martinez (34.5), Miguel Cabrera (30.7) and outfielder J.D. Martinez (15.5) are the only Tigers regulars with above average numbers for RE24.  Using RAA, all of the regulars other than the shortstops are above average.  

Additionaly, Victor Martinez (3.1) and Cabrera (+3.0) are the only hitters with positive RE24-RAA differentials.  So, most of the Tigers are not doing so well in plate appearances where there is high run expectancy.  Most notably, catcher Alex Avila has a differential of -9.5 and right fielder Hunter -9.1.

Table 1: RE24 for Tigers as of August 21, 2014

Name	RE24	RAA	RE24-RAA
Victor Martinez	34.5	31.4	3.1
Miguel Cabrera	30.7	27.7	3.0
J.D. Martinez	15.5	19.1	-3.6
Rajai Davis	-1.4	4.2	-5.6
Ian Kinsler	-1.9	4.4	-6.3
Austin Jackson	-2.3	3.6	-5.9
Eugenio Suarez	-3.1	-0.9	-2.2
Torii Hunter	-3.2	5.9	-9.1
Nick Castellanos	-3.6	0.8	-4.4
Alex Avila	-7.8	1.7	-9.5
Andrew Romine	-17.6	-10.2	-7.4

Data source: FanGraphs.com